A campaign ad produced by President Obama’s reelection team that questions whether presumptive GOP nominee Mitt Romney would have ordered the Special Forces raid that killed Osama bin Laden is generating considerable controversy in US politics, in advance of the anniversary of the raid.

Mr. Obama’s supporters have defended the ad, saying the president had long pressed his national-security apparatus to find the Al Qaeda leader. Obama then made a courageous decision to approve a raid despite less-than-perfect intelligence about Mr. bin Laden’s whereabouts, they say.

Mr. Romney, in his first run for the White House in the 2008 cycle, had questioned whether targeting one terrorist leader was a good use of US military resources.

The ad was “not over the line," said Robert Gibbs, a senior adviser to the Obama reelection campaign. "There’s a difference in the roles they would play as commander in chief, and I certainly think that’s fair game.”

But Republicans and even some Democrats are questioning the propriety of invoking bin Laden’s killing in such nakedly political terms. It’s one thing to promote the president’s role in bringing justice to one of the nation’s primary enemies, noted Sen. John McCain (R) of Arizona, Obama's opponent in 2008. It’s quite another to spin that event into a political attack ad.

“Shame on Barack Obama for diminishing the memory of September 11th,” said Senator McCain in a statement issued by the Republican National Committee last Friday.

Over the weekend, senior Romney adviser Ed Gillespie said on NBC’s “Meet the Press” that Obama was turning an event that had unified the nation into something divisive. By the time Obama had to make the “go” decision on the raid, it was not that difficult an executive call, Mr. Gillespie implied.

“I can’t envision, having served in the White House, any president having been told, ‘We have him, he’s here, you know, should we go in?’ and saying, ‘No, we shouldn’t,' ” he said.

The ad is the sort of political discourse that “makes politicians and political leaders act irrationally when it comes to matters of war because they’re so afraid to be called wimps,” said Ms. Huffington.

So why did the Obama team launch such a potentially controversial ad? Almost certainly, one reason is that it highlights an Obama strength: Voters rate his foreign-policy decisions higher than his economic ones.

Plus, national security is often an area of weakness with Democrats. As author and former Newsweek editor Jon Meacham notes in Time magazine, Democratic presidential candidates have continually learned the lesson that they have to act tough to counteract the GOP’s inherent advantage on defense issues.

“The lesson of the Clinton years and of Obama’s win of both the nomination and the general election in 2008 is that Democrats need to be as tough as [John F. Kennedy] was,” Mr. Meacham writes.

Finally, Wednesday is the anniversary of bin Laden’s death. With the subject resurfacing in the media, the Obama team probably felt they should act fast to define the subject in the way most favorable to them. [Editor's note:The original version of this paragraph listed the incorrect day for the anniversary.]

“Is the bin Laden ad fair to Romney? No, not really. But politics is not for the faint of heart,” writes Meacham.